Automatic ringing system.



H. D. CURRIER & M. B. STAZAK.

AUTOMATIC RINGING SYSTEM. APPLICATION FILED JAN-9. I915.

. Patented Aug. 20, 1918.

Iii/52775115" HzbamZZEurrzPr m'afiaszfi.5flizak Ill UNITED STATES PATENT omnicn.

HIRAM n; CURRIERAND MICHAEL B. s'rnznxgor cmcnco, ILLINOIS, nssrenons'ro KELLOGG SWITCHBOARD & TION OF ILLINOIS.

SUPPLY COMP-ANY, or crncaeo, ILLINOISQA oonronamrromsrrc nine-me srs'rnm.

. specification of Letters Ifatent. Patented Aflg, 20,1918;

Application filed January aisle. Serial No. 1,307.

Our inventionrelates to telephone systems,

and has to do more particularly with automatic ringing systems, such as are provided in operators link circuits, and one of the principal objects of our invention is to provide an improved circuit arrangement whereby the applied ringing current is disconnect.-

ed from a called line immediately upon the removal of the receiver-by a subscriber thereat whether during a silent or ringing inter val, so as not to ring thecalled subscriber in the ear in the event that the called subscri'ber answers during the said ringing interval.

Referring to the accompanying drawing, we have illustrated the preferred embodij ment of our inventionand have shown two substations A and B terminating in line circuits L and L respectively, each comprising the usual line relay LR, c t-ofl relay CO, multiple line jacks J andline s gnals S. The line circuits illustrated are known as multiple line lamp circuits in which a line lamp is provided for each line jack so that when a call is initiated, a lighted line signal appears before-each ofthemultiple line jacks so that any one of a number of operators may answerthe call to the exclusion of the others.

The cord circuit ing plug. AP and a calling plug GP connected by the heavily marked talking conductors. Upon the initiation ofa call the operator answers by inserting an answering.

plug AP into a multiple jack .1 causingthe energization of a high resistance test relay T which connects an answering sleeve supervisory relay AS in series circuit with a relay C0 of the line'circuit L, the relay AS operating to connect'the operators set Qto T the cord circuit. The answering tip super visory relay AT is also energized to prevent answering supervisory lamp AL from lighting prematur'ely. Upon the insertion of a Station A initiates a call, the line relay LR call plug GP into the multiple jack J of a called line, a calling sleeve supervisory relay CS is operated to disconnect the operators (l comprisesan answerset 0. from the cord circuit. One of a plurality of ringing pluhgers of the ringing key BK is then depressed, which connects the proper ringing frequency to ring the call bell of thecalled substation. The comalso actuated while the plunger is in its fully depressed position. to close an energizing ircuit for a ringing disconnect relay RD, which'in turn closes an energizing circuit for an interrupter relay RT which is alternately energized and deencrgized by the interrupt-er I to intermittently connect ringing currentto thewanted line. A meter'relay MR and a meter magnet -MM are also. provided which are operated when the common contacts are closed, to cause the meter to mon contacts 1011 of the ringing key are register. A trip relay TR,,preferably of high resistance and non-inductive to ringing current, s provldedwhich is energized upon station, to disconnect ringing current from the called line should the subscriber the'r'eatv remove his receiverduring a ringing-interval. A callingtip supervisory relay CT is also provided and is energized upon the re sponse of the called substation. That is, if relay BI is back at the time of responding relay CT comes up immediately, but if rclay R1 is up, then relay TR comes up followed. by the'restoration of RI), RI and char I gization of CT.

Should the calling subscriber replace his receiver before thecalled subscriber answers, a link disconnect relay LD is 1 energized which causes the deenergization of the relays RD and 111' to interrupt the ringing current which is being intermittently connected to .the called line. The energization of the relay LD also caused the disconnection of the link conductors from the calling line which causes the restoration of the connected line circuit to normal to permit the calling subscriber to immediately recall without awaiting the removal of the answering plug AP from the connected jack.

; .Having described in general the apparatus used in establishing a connection between a calling and called substation, we will now describe "the preferred embodiment of our invention more in detail.

Assuming now that a subscriber at subis energized closing a circuit for the line signals S.- An operator now seizes the call '75 i the removal of the receiver at the called sub by inserting the answerin plug AP into one of the multiple jacks of the calling line. The high resistance test relay TE is energized to close its alternate contact I which closes aseris energizing circuit including relay AS and cut-ofi' relay CO. The relay AS is now connected to the sleeve of the cord independently of the contact 1 of the relay TE by way of its contact 2 and the flow of battery current over the line also energizes the answering tip supervisory relay AT which opens its normal contact 3 to prevent the lighting of the answering supervisory lamp AL. The closure of alternate contacts 4, 5 of relay AS connects the operators set C to the cord circuit by way of conductors 6 and 7, and the normally closed contacts 8 and 9 of the calling sleeve supervisory relay CS. Should a second operator attemptto answer the initiated call, the low wound answering supervisory relay AS of the first cord circuit C prevents the high resistance relay T of the second cord circuit from operating due to the shunting effect of the relay AS of the first cord circuit C, and the second operator not being able to communicate with the calling subscriber, removes his answering plug AP from the jack.

The connected operator now ascertains the wants of the calling subscriber, and assuming that substation B is wanted, she tests in the usual manner and assuming that the line is idle, inserts the calling plug CP into a jack J of the Wanted line. The nsertion of the calling plug CP closes a series energizing circuit including relays CS and the cut-01f relay CO and the relay CO energizing removes the substation control of its line signals and extends the connected cord to the wanted line. The relay CS upon energization opens its normal contacts 8 and 9 to disconnect the operators set 0 from the cord circuit, and also closes a circuit for the signal CL from battery through the said lamp normal contacts 14, 1 5 and 16, conductor 17, normal contact 12 to ground at alternate contact 13, thus lighting the signal CL.

The operator now depresses the proper ringing plunger of the ringing key RK to connect the proper frequency, of ringing on rrent to the called line. The ringing key RK upon being depressed to its fully operated position, also closes the common'contacts 10 and 11 but when the key plunger assumes its indicating position the common contacts restore to normal. The closure of alternate contact 10 closes an energizing circuit for the meter relay MR traced from battery through the winding of said relay, alternate contact 10, normal contacts 14, 15 -and 16, conductor 17, normal contact 12, to ground at alternate contact 13 of relay CS. The relay MR closes its alternate contact 30 contact 13 to ground. The relay RD then closes a locking circuit for itself, traced from battery through its winding and alter- .nate contact 14, normal contact 15, normal contact 16, conductor 17, normalcbntact 12, the alternate contact 13 to ground. T be opening of alternate contact 14 of RD offaces the signal CL and the closure of the alternate contact 18 of relay RD closes an energizing circuit for the relay RI traced from battery through the constantly rotating interrupter I, winding of said relay RI to round at alternate contact 18.

he relay RI is thus alternately energized and deenergized, to connect ringing current to the called substation D, the circuit for the ringing current being traced from the connected generator Gr through the closed contact of the depressed ringing plunger, alternate contact 19, condenser K, alternate contact 20, part through the winding of relay TR to ground and-part over conductor 21, alternate contact 22, alternate contact 23, the tip contacts of the connected plug and jack, through the condenser and call bell of the called substation B, sleeve contacts of the connected plug and jack, then dividing,part flowing through relay CS and part through alternate contact 24, through the winding 25 of the relay AT to battery and ground. This ringing current being thus intermittently connected to the called substation until the called subscriber thereat answers. The winding 25 of the relay AT is of few turns, and the ringing current passing through the said winding induces only sufiicient current into the, winding 26 of the relay AT to give an audible signal to the calling subscriber to notify him that ringing current is being applied. The tip relay TB is not energized by the ringing current, this result being assisted by interposing the condenser K which reduces the peak in the voltage but still permits of ringing over lines of considerable resistance. The copper shield on the core of relay TR also results in a non-inductive ef feet.

The subscriber at the substation B in answer to his call removes his receiver from its switch-hook, and assuming that he has removed the receiver during a ringing interval, an energizing circuit for the trip relay TB is established caused by a flow from battery through the winding 25 of the relay AT and the winding of CS, the sleeve contacts of the connected plug and jack through the closed contacts of the switch-hook at the substation B, the tip contacts of the connected plug and} jack, alternate contacts 23, 22, through the winding of relay TR to ground. The relayTR upon energization from battery through the winding of relay CS, sleeve contacts of the connected plug and jack through the substation B, the tip contacts of -.the connected plug and jack,

alternate contact 23, normal contact 22 of relay RI, through the winding of relay CT toground. In fact, relay CT is simply substituted for relay TR.

Should a called subscriber respond during the silent interval, that is, when the relay RI is denergized, a-circuit for tip relay CT is established traced from ground through the winding of CT, normal contacts 19, 22,

alternate contact 23, over the called line 1'6.

turning through the winding of CS and the winding 25 of AT in multiple to battery. Therefore relay CT interrupts its normal contact 12 removing the ground connection forthe ringing disconnect relay RD which restores and by the opening of its alternate contact 18 prevents further energization of RI. The subscribers at the substations A and B having finished conversation replace their 1 receivers upon their respective switch-hooks.

The replacing. of the receiver at B opens the energizing circuit of relay CT which deenergizes and establishes an energizing circuit for the calling supervisory lamp CL, traced from battery through the said lamp, normal contacts 14, 15 and 16, conductor 17 normal contact 12, to ground at alternate contact 13, lighting said lamp. The subscriber at substation A replacing his receiver opens the energizing circuit of relayAT, and the closing of the normal contact 3 thereof establishes an energizing circuit for the link disconnect relay LD, traced from battery through the winding of the said relay, normal contact 3, alternate contact 27 to ground at alternate contact 13 of relay CS.' The deenergization of relay AT alsocldses an energizing. circuit for the answering superlamp, normal contact 3, alternate contact 27, to ground at alternate contact 13. The

initial energizing circuit for lamp CL was interrupted when the relay LD was energized but another circuit for the said lamp is established from battery through the said lamp, normal contact 10, alternate contact 16, conductor 17, normal contact 12, alternate contact '13 of relay "CS to ground. Armature contact 16 simply shifts the circuit. The relay LD energizing opens the cord conductors at its contacts 28, and 29,

openin the series circuit for the relays CO and A Relay CO deenergizing restores the line circuits of the calling line to normal placing it in condition for an immediate recall so that if the subscriber at substation A again removes his receiver the line relay LR 1s energized to lightthe multiple line signals so the same operator or another operator may seize the recall without awaitin% the removal of the plug AP.

he energizing circuit for the relays AS and TE is interru ted when therelay LD energizes but a su stitute circuit is established through alternate contact 29 of relay LD, normal contact 3 and alternate contact 27 to ground at alternate contact 13. This continued energization of relay AS keeps the supervisory lamps AL and CL lighted and the operator therefore removes the plugs AP and CP from their connected Jacks. Upon removal of the plug CP the de'energization of the relays CS and CO is brought about. The restoration of relay CS causes alternate contact to assume its normal position thus opening the circuit for the re lays LD, T and AS and also efi'acing the signals AL and CL. The apparatus at the cord C isnow at normal and the cord is available for making other connections.

It will be noted that relay L1) is a slow restoring type, this being? to prevent the seizing of'a recall by more than one link circuit. That is, assuming a connection is established between substations A and B and that after conversation the subscribers have replaced their receivers to bring about the lighting of lamps AL and CL and the energization of LD. .Should the calling. sub-r scriber at A initiate a recall prior to the removal of plug AP, the associated line sig nals will of course be lighted and should another operator than the onewhich controls cord C seize this call, uponthe withdrawal of plug CP of C the locking circuit for relays LD, TE and AS is interrupted at alternate contact 13 of US. Now if relays LD,

' TE and AS were fast relays, and relay LD visory lamp AL from battery through said i should restore prior to TE and AS it will be seen that due to the closing of normal contact 29 of LD, relay AS would remain locked up over the sleeve strand and therefore the operator of cord C would have her. telephone connected to the calling line in multiple with the telephone of the other operator who has seized the recall. I But due to the slowness of relay LD, relays AS and TE will restore prior to LD, so that upon restoration of LD the associated relay TE will not again energize and therefore itsrelay AS also remains inert and the operator at C is prevented from comlng in on the seized recall.

Although we have chosen a referred embodiment for the purpose of il ustrating our invention, we contemplate using it in other ways than that shown,and therefore we do not desire to be limited to the exact structure as shown and described, but aim to cover all that which comes Within the=spirit and scope of the appended claims. 7

Having described our invention, what we claim as new and desire tosecure by United States Letters Patent, is:

1. An automatic ringing system including a link circuit having calling terminals for connection with a called line, a grounded source of ringing current and a grounded trip relay having their ungrounded terminals connected, a calling tip relay, means for alternately connecting the tip relay and the generator and trip relay in circuit with the calling terminal to intermittently apply ringing current to a connected called line, and means whereby one or the other of said relays will operate according to which one is connected at the time a response is socured to prevent further application of ringing current.

2. A telephone system including telephone lines, a link circuit having calling terminals for connection with called ones of said lines,

a source of ringing current and a trip relay, a condenser interposed 1n a connection extending between terminals of said relay and generator, means for intermittently connecting and disconnecting said condenser and relay to one of said calling terminals for intermittently applying ringing current to a connected called line, a source of direct current, means for connecting said source in operative relation with said relay when a response from the connected line is secured for operating said relay, and circuit changes efi'ective responsive to such operation of the relay to prevent further application of ringing current. V

3. A telephone system including telephone lines, a link circuit having calling terminals for connection with called ones of said lines, a source of ringing current, a trip relay, and a tip relay, means for alternately connecting the tip relay and the generator and trip relay in circuit with the calling terminal whereby ringing current is intermittently applied to a connected called line, and means whereby one or the other of said relays will operate according to which one is connected at the time a response is secured to prevent further application of ringing current.

4. A telephone system including telephone lines, a link circuit having calling terminals for connection with said lines as called lines, a source of ringing current, a pair of line operated relays, means for alternately connecting said ringing source and one of said relays and then the other of said relays in circuit relation with a calling terminal to intermittentl apply ringing current to a connected ca led line, means' whereby either one of said relays is operated when a response is secured according to which one is connected at, the time of response, and circuit connections controlled by the operated relay for preventing further application of ringing current.

5. A telephone system including a called telephone line, a link circuit provided with a terminal for connection with said called line, a source of ringing current and a trip relay, means for simultaneously intermittently connecting said relay and said source of current in multiple to a contact of said terminal, and means controlled at the substation of said line for energizing said trip relay to disconnect said source of current.

6. A telephone system including a called telephone line, a link circuit provided with a terminal for connection with said called line, a source of ringing current and a trip relay, means for intermittently connecting said relay and said source of current in multiple to a contact of said terminal, and means controlled over the called line for operating said relay during the period said source of current is connected to said contact to disconnect said source of current from said contact.

7. A telephone system including a called subscribers line, a source of ringing current adapted to be connected to said line, a pair of trip relays, means for alternately connecting said relays to said line, and-means controlled at the substation of the called line for energizing'one of said relays according to which one is connected at the time a response is secured to prevent a further application of ringing current.

- 8. A telephone system including a called subscribers line, a trip relay and a ringing current generator having terminals connected together, a second trip relay, means for alternately connecting said relays to said called line whereby ringing current is intermittently connected to said called line, and means controlled over said called line for operating one of said relays depending upon which one is connected at the time a response is secured to prevent further application of ringing currentto the called line.

9. A telephone system including a called subscribers line, an interrupter relay, a trip relay anda source of ringing current provided with terminals connected to a contact of said first relay, a supervisory relay connected to another contact of said interrupter relay, means for energizing and denergizing said interrupter relay for intermittently connecting ringing current to said called line and for alternately connecting said trip and supervisory relays to said called line, and means controlled at the substation of said called line for energizing said trip or said names? 1 relay and a source of ringing current having terminals connected to a source of direct current and other terminals connected to a contact of said interrupter relay, a supervisory relay connected to a contact of said interrupter relay, means for operating said interrupter relay for alternately connecting said trip relay and said supervisory relay tosaid called line, and a circuit controlled at the called substation including one of said relays in circuit with said source of direct current for disconnecting said ringing current from said called line.

11. A telephone system including a subscribers line, a source of ringing current, a trip relay, means for intermittently multiply connecting the said relay and the said source of current to said line, and means controlled over the called line for operating said relay to disconnect said source of current from said line.

12. A telephone system including a called subscribers telephone line, a grounded source of ringing current, a trip relay having one of its terminals connected to ground, means for multipl connecting said relay and said source 0 current to said called line, and subscriber-controlled means for operatively energizing said relay to cause said source of current to be disconnected from said line.

13. A telephone system including a sub-- scribers line, a source of signaling current for connection to said subscribers line, a pair of trip relays, means for alternately connecting said relays to said subscribers line, and means controlled by either of said relays for preventing further application of said signaling current to said line.

14. A telephone system including a called subscribers line, a source of ringing current adapted to be applied to said line, a pair of relays, means for alternately connecting said relays with said line, and means controlled over the called line for operating either of said relays to prevent further application of purrent from said source of current to said 15. A telephone system including a subscribers line, a source of ringing current, means for connecting said current to said subscribers line, a relay adapted to be connected to said subscribers line each time said ringing current is connected thereto, a second relay adapted to be connected to said subscribers line each time said ringing current is disconnected therefrom, and subscriber controlled means for energizing either of said relays to prevent a reapplication of, said ringing current to said subscribers line.

Signed by us at Chicago, county of Cook and State of Illinois, in the presence of two witnesses.

HIRAM D. OURRIER. MICHAEL B. STAZAK.

Witnesses:

GEORGE E. MUELLER, M. R. Roormom). 

